1. Field of the Invention
The invention relates to a light source device which is installed and used in a projection device, such as, for example, a projector device of the projection type or the like.
2. Description of the Prior Art
Currently, a type of light source device which is installed in a projection device, such as, for example, a projector device of the projection type or the like, as is shown, for example, in FIG. 5, has an essentially box-shaped housing 61 which is provided with a light exit opening 62, and a light source lamp 70 which is located in this housing 61. The light emitted from this light source lamp 70 is focused by means of a concave reflector 80 and is projected via the light exit opening 62. In order to increase the efficiency of the light from the light source lamp 70, there is, for example, a spherical reflector 81 in front of the concave reflector 80 with respect to the light exit direction.
In this light source device 60, there is a transparent window component 65 so that the light exit opening 62 of the housing 61 is closed from the outside. This yields a state in which the inside of the housing 61 is hermetically sealed. Accordingly, in operation of the light source lamp 70, the light source Tamp 70 and the two reflectors 80, 81, reach an extremely high temperature. Therefore, an arrangement is undertaken in which the light source lamp 70 and the two reflectors 80, 81, are cooled by, for example, cooling air being delivered into the housing 61 via an air inlet opening 63 for the cooling air supply which is formed in the housing 61. In FIG. 5, an evacuation opening 64 for evacuation of the cooling air is also shown.
For the light source lamp 70, a discharge lamp of the short arc type is used which has a bulb which, for example, has an arc tube 71 and hermetically sealed tubes 72A, 72B, which border the opposite ends of the arc tube 71, and in which an anode 75 and a cathode 76 disposed opposite each other in the arc tube 71. Additionally, the arc tube 71 is filled, for example, with xenon gas.
The anode 75 and the cathode 76 are each attached and held on the tip of a lead pin 77 that is made, for example, of a tungsten pin. The respective lead pin 77 extends into the hermetically sealed tubes 72A, 72B, along their tube axes to the outside. The base areas thereof project over the outer edges of the hermetically sealed tubes 72A, 72B. On the outer ends of the hermetically sealed tubes 72A, 72B, the hermetically sealed tubes 72A, 72B are sealed on the lead pins 77, for example, by graded glass, by which hermetically sealed parts are formed.
In this light source lamp 70, a base 79 is installed in the hermetically sealed tube which is located behind the light exit opening, specifically in the cathode-side hermetically sealed tube 72B. This base 79 is supported in the housing 61 by a holding component 66.
In recent years, there has been a tendency to carry a projection device, in which such a light source device has been installed, back and forth and to use it at different locations. Therefore, there is a need to reduce the size of the projection device, and with respect to the need, it is necessary, for example, to reduce the size of the light source device.
One means for reducing the size of the light source device was, for example, to make the light source lamp inherently smaller. In the case of an arrangement in which simply the light source lamp is made small, in operation of the light source lamp 70, the distance between the base area of the anode 75 and the region of the hermetically sealed tube 72A, which region is hermetically sealed, for example, by graded glass on the lead pin 77, becomes small, by which the anode 75 which reaches an extremely high temperature during operation of the light source lamp 79 approaches the hermetically sealed part. Therefore, the disadvantage arises that the hermetically sealed part reaches a high temperature, and thus, the bulb tends to become damaged.
Against this disadvantage, there is a measure which is described in Japanese utility model JP 2532712 Y2. Here, a cooling rib is placed, for example, on the lead pin which extends projecting to the outside from the hermetically sealed part to prevent the temperature of the hermetically sealed part of the light source lamp from rising. This cools the lead pin.
Another measure is disclosed in commonly owned Japanese patent application JP 2003-132845 A. Here, for example, in the periphery of the lead pin, proceeding from the outer peripheral area of the lead pin, there are several air guide plates arranged in the radial direction at distances relative to one another such that they extend in the axial direction. In the gaps between the lead pin and the air guide plates, cooling air can flow and thus cools the lead pin.
In the above described technology, the effect of cooling of the lead pin can be adequately obtained. However, it was found that the following disadvantage arises in both cases:
In the light source lamp, there are specifically cases in which the bulb breaks during operation, since the internal pressure in the arc tube during operation becomes extremely high. In the light source device 60 with the above described arrangement, since only one of the hermetically sealed tubes of the light source lamp 70, i.e., only the hermetically sealed tube 72B, is supported (unilateral support arrangement), there are cases in which the window component 65 is damaged by the fragments of the bulb flying around and colliding with the window component 65. In particular, when the window component is damaged in the state in which the light source device is installed in the projector device, adverse effects are exerted on the devices in the peripheral vicinity of the projector device.